I believe KISSlicer uses slower speeds by defaultdanlad1631 wrote:Ok, I'll give that a go. I can't understand how kisslicer doesn't give the same results with the same speed settings. Thanks for the help.
Re: Start layer blobbing?
Re: Start layer blobbing?
I notice something in your last picture that looks exactly like a problem I was running into with any sharp corner. It appears to be caused by a momentary, no matter how brief, pause in axis travel. When traveling in one direction I observed a brief pause when switching to the "other" axis of travel. For example, when traveling in the X-axis and upon reaching a corner the x-axis stepper stops and THEN the y-axis stepper starts. This pause is short but enough time to allow the still-extruding plastic to leave just a "little" extra on that corner which translates to a blob in the corner. So, to test my theory, I started putting extremely small fillets on ALL corners... viola, problem seems to disappear. The small radius allows the steppers to coordinate around the radius and thus cause a smooth transition between axis movement without introducing a pause or a noticeable radius on the part. Your extrusion is round anyway so you really can't detect a very minimal intentional radius but it does introduce a difference in the g-code.
I agree that different slicers handle this differently and, as a software engineer, could theorize several possible causes that range from compiler issues, communication protocols, etc. But I have observed this behavior in most slicers with some geometry (some on inside corners, some on outside perimeters only, etc) and I am finding that small design considerations can eliminate these issues across the board.
I agree that different slicers handle this differently and, as a software engineer, could theorize several possible causes that range from compiler issues, communication protocols, etc. But I have observed this behavior in most slicers with some geometry (some on inside corners, some on outside perimeters only, etc) and I am finding that small design considerations can eliminate these issues across the board.
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danlad1631
- Posts: 29
- Joined: Sat Aug 30, 2014 1:11 pm
Re: Start layer blobbing?
I can see exactly what you mean. Apart from having to remodel everything I download from Thingiverse, which is impractical, what's the other solutions? Stick with a freeware slicer that does a much better job with sharp corners...
I can see it with my own eyes. As it finishes the last outer perimeter it stops for a second then moves to start the next layer, this is where the problem is. I've tried coasting settings from 1 to 5mm and it does nothing. I've tried changing to negative restart, I've tied changing the print speed, the X/Y speed, the multiplier, the width, the this and the that.
Where are the developers in all of this? A little input from them wouldn't go a miss.
Refund would be nice at this point!
I can see it with my own eyes. As it finishes the last outer perimeter it stops for a second then moves to start the next layer, this is where the problem is. I've tried coasting settings from 1 to 5mm and it does nothing. I've tried changing to negative restart, I've tied changing the print speed, the X/Y speed, the multiplier, the width, the this and the that.
Where are the developers in all of this? A little input from them wouldn't go a miss.
Refund would be nice at this point!
Re: Start layer blobbing?
dan, this is not official support. this is a place where users help users. if you want get input from the developers/support then you need to email them. support and the dev team dont post here. with that said, if you retract enough to relieve the pressure then coast a bit, add some wipe and neg restart....all in the right amounts so your all tuned in you will control the blobs. doesnt matter who's slicer you use, if you have hot plastic under psi in the hot end its gonna run out and make a blob at the start or end of the line. s3d has just a ton of settings for you to control all this. try turning your temp down as well. the hotter your runnin the more the nozzle will drool.
Re: Start layer blobbing?
Hi Jimc
All the above comments seem very relevant, I would also like you to check how much wobble you have a the end of the extruder, on a couple of printers I have fixed up the retraction of the filament but ended up with little bumps at the change of direction it may just be worth a look at this. If you find a looseness in the belts or mounts and you can't adjust for, some help can be had by retracting the level of the bed this can give the nozzle time to move back to it normal position (not a complete fix but it may help and any changes would be diagnostic).
If you set the start point for each layer to be random this also help as the direction and position of the nozzle starting will be different at each layer this may not fix but would also help in the diagnosis.
I like the way we all see the problem differently there just so many variables to work with.
I will be away for a day or two with very limited internet and I am on the other side of the world to you, but I will try to follow up when you have given the above a try.
Enjoy your day, it raining here and I off for a break by the water and was hoping to do some paddling around but maybe I will just read and watch the rain
Andrew (Sydney Australia)
All the above comments seem very relevant, I would also like you to check how much wobble you have a the end of the extruder, on a couple of printers I have fixed up the retraction of the filament but ended up with little bumps at the change of direction it may just be worth a look at this. If you find a looseness in the belts or mounts and you can't adjust for, some help can be had by retracting the level of the bed this can give the nozzle time to move back to it normal position (not a complete fix but it may help and any changes would be diagnostic).
If you set the start point for each layer to be random this also help as the direction and position of the nozzle starting will be different at each layer this may not fix but would also help in the diagnosis.
I like the way we all see the problem differently there just so many variables to work with.
I will be away for a day or two with very limited internet and I am on the other side of the world to you, but I will try to follow up when you have given the above a try.
Enjoy your day, it raining here and I off for a break by the water and was hoping to do some paddling around but maybe I will just read and watch the rain
Andrew (Sydney Australia)
Re: Start layer blobbing?
First, I suggest the OP looks at the custom start code in the slicing software that gives the better results. There may be a command in that which is affecting his results. Also the extruder retraction setting (how much and what speed is the retraction set to?) Some extruder designs require longer retraction than other types - typically 4mm at least for a Bowden extruder. One other factor to fiddle with is acceleration (set in the printer by means of the M202 command if supported). When the direction of travel changes fro X to Y, one axis must decelerate to 0 and the other start to accelerate. This means that there has to be a (very brief) moment when both motors are stopped. The acceleration parameter will determine how long the nozzle is in the very slow region of travel.
Dave
Dave
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danlad1631
- Posts: 29
- Joined: Sat Aug 30, 2014 1:11 pm
Re: Start layer blobbing?
Thanks for all the help you people have given me, I've been able to get some really good prints.
I've tried to print something today though and as you can see in the pictures, it's not the best print in the world, any thoughts on whats causing this? The bridging is not great and the start/end point is terrible, it seems to improve to further up the model. When I print other objects they seem to come out ok with the current settings.
Attached is my factory file and 2 images.
Thanks again for the help.
I've tried to print something today though and as you can see in the pictures, it's not the best print in the world, any thoughts on whats causing this? The bridging is not great and the start/end point is terrible, it seems to improve to further up the model. When I print other objects they seem to come out ok with the current settings.
Attached is my factory file and 2 images.
Thanks again for the help.
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- Lamp_Snap_Luxo (repaired).factory
- (435.94 KiB) Downloaded 381 times
Re: Start layer blobbing?
Any bridge with a hole in it is going to have problems. Firstly the perimeters of the hole will be printed in mid-air, and secondly there is no way to bridge across the hole so the bridging infill has to stop in mid-air. The usual way to overcome the problem is by making the first bridge layer solid (no hole) so as to create a membrane that the hole can be printed onto in subsequent layers. After printing, the 1-layer membrane is drilled or pushed out. That requires a modification to the design or STL - easy if it is your own design, but will require a way to edit the STL if it is a Thingiverse item.
As for the blobbing problem - if KissSlicer does not have that problem I suggest you look for every difference in the settings you have between that application and S3D. One thing I can think of is that maybe KissSlicer is printing outer perimeters first, while S3D is printing them last. You can easily change that in S3D. Having outer perimeters printed first can move the blobs from the outside to the inner perimeter where it is not noticeable.
Dave
As for the blobbing problem - if KissSlicer does not have that problem I suggest you look for every difference in the settings you have between that application and S3D. One thing I can think of is that maybe KissSlicer is printing outer perimeters first, while S3D is printing them last. You can easily change that in S3D. Having outer perimeters printed first can move the blobs from the outside to the inner perimeter where it is not noticeable.
Dave
Re: Start layer blobbing?
I have noticed that if you run two processes: 1- With "Extra Restart Distance" set to some positive value (probably for support material that needs ooze control) 2- With "Extra Restart Distance" set to zero (for build material that needs no ooze control). The first process will override the second process and SD3 will proceed to dump a huge blob of material out where you have explicitly told it not to using the restart distance specified for the first process in the second process. It must be a bug... Hopefully they will fix it...
Re: Start layer blobbing?
I am having a similar issue. Are you running multiple processes on multiple parts when you print this? Can you see the extruder stepper motor running while the head is not moving at the start of each layer (where it makes the blob)? I have a ticket open with SD3 support so I will see what they come back with. I will post again if I can get the issue fixed. Here is what I am dealing with:
No matter what I do, the ooze control from the first process in the list is overwriting the ooze control for other subsequent processes. So for this instance, I am applying the "Purge Box" fff to the inner box that is to be PVA. So I need a lot of retraction to control the ooze as well as a lot of restart distance to get it back extruding again. I create this profile and select the model(s) I want to apply it to. Great. Here are the problems that creates:
Problem 1: The ooze control settings for "Purge Box" are being applied to "Purge Perimeter" where I just want a simple ABS extrusion on the right nozzle with just 1.75mm of retraction and no extra restart distance. So I am getting a full 10mm of extra restart distance no matter what I select for that process. It overwrites and applies to all models, I have tried to add more models and more processes to the build and it is the same thing.
Problem 2: The extra restart distance on the left nozzle is reversed. It retracts instead of extrudes. I have tried negative values in the box and it still does the same thing. So I can only retract with the left nozzle. With 10mm of retraction applied twice, the filament is completely pulled out of the nozzle.
Problem 3: If explicitly tell SD3 that I want the infill with the left nozzle. When I apply this process to the inner box, it just goes ahead and fills it with the right nozzle. It doesn't matter what I change, it will only fill using one nozzle or the other in a single process. You have to use a single nozzle for an entire part and cannot get SD3 to apply fills with the other nozzle.
I have tried all the obvious things like recreating profiles, reloading firmware, etc. It just seems that SD3 has no support for multi-nozzle machines. It also doesn't seem to correctly apply separate processes to different models on a single build. I am building this stupid box in the picture because I will have to put it next to each part so that the second nozzle stays flowing on larger parts. By the time the machine builds a raft, the second nozzle is frozen up and needs a serious purge before it gets flowing again. Then it oozes everywhere. And I obviously can't control the ooze. So the "purge box" is going to be built along side my part to keep things flowing the left extruder. So this is really a problem created by another problem. Hopefully it will get fixed... I really like the lines that SD3 creates with it slicing algorithm and want to use it. I just can't in it's current state given these bugs.
No matter what I do, the ooze control from the first process in the list is overwriting the ooze control for other subsequent processes. So for this instance, I am applying the "Purge Box" fff to the inner box that is to be PVA. So I need a lot of retraction to control the ooze as well as a lot of restart distance to get it back extruding again. I create this profile and select the model(s) I want to apply it to. Great. Here are the problems that creates:
Problem 1: The ooze control settings for "Purge Box" are being applied to "Purge Perimeter" where I just want a simple ABS extrusion on the right nozzle with just 1.75mm of retraction and no extra restart distance. So I am getting a full 10mm of extra restart distance no matter what I select for that process. It overwrites and applies to all models, I have tried to add more models and more processes to the build and it is the same thing.
Problem 2: The extra restart distance on the left nozzle is reversed. It retracts instead of extrudes. I have tried negative values in the box and it still does the same thing. So I can only retract with the left nozzle. With 10mm of retraction applied twice, the filament is completely pulled out of the nozzle.
Problem 3: If explicitly tell SD3 that I want the infill with the left nozzle. When I apply this process to the inner box, it just goes ahead and fills it with the right nozzle. It doesn't matter what I change, it will only fill using one nozzle or the other in a single process. You have to use a single nozzle for an entire part and cannot get SD3 to apply fills with the other nozzle.
I have tried all the obvious things like recreating profiles, reloading firmware, etc. It just seems that SD3 has no support for multi-nozzle machines. It also doesn't seem to correctly apply separate processes to different models on a single build. I am building this stupid box in the picture because I will have to put it next to each part so that the second nozzle stays flowing on larger parts. By the time the machine builds a raft, the second nozzle is frozen up and needs a serious purge before it gets flowing again. Then it oozes everywhere. And I obviously can't control the ooze. So the "purge box" is going to be built along side my part to keep things flowing the left extruder. So this is really a problem created by another problem. Hopefully it will get fixed... I really like the lines that SD3 creates with it slicing algorithm and want to use it. I just can't in it's current state given these bugs.
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